From what I've read (on RDR, Nerd, etc.) is that homogenous pieds always have a "normal" head, usually with a bit of gray on the neck, and then mixed amounts of white and "piebald" orangey-black markings. Lots of white is referred to as "high-white pied"; very little white is "low-white pied".

Piebalds, however, are starting to be mixed with other morphs and with those, you may be able to eventually see one that has a white head - but to my knowledge (i.e., surfing the web for any and all pictures of pieds I can get my grubby hands on), there is no current pied morph combo that has a white head.

Time to combine a super mojave x piebald, ivory or yellow-belly x piebald, lesser platty x piebald, etc.? =)